1. Technical Field of the Invention
The present invention relates generally to a revetment block. More particularly, the invention relates to a revetment block, used to form a revetment mat having interlocking qualities which inhibit vertical hydraulic lifting forces as well as inhibiting motion in longitudinal and latitudinal directions. Additionally, a revetment mat is disclosed being formed of the above described revetment block thus inhibit upward thrust on the mat.
2. Description of the Related Art
Revetment mats are used to inhibit soil erosion from areas of flowing water along, for instance, shorelines, spillways, overflow channels, drainage channels, boat ramps, and the like. Current revetment mats are formed from articulated concrete blocks that interlock together and conform to specific hydraulic performance characteristics.
In U.S. Pat. No. 4,370,075, issued to Scales, FIGS. 1 and 6 show a common characteristic of revetment mats. FIG. 6 shows a perspective view of a revetment block having a plurality of protrusions which may be slidably positioned within a similarly shaped channel of an adjacent block. As viewed in FIG. 1, it is clear that the blocks would be susceptible to hydraulic lift without the use of a cable because the blocks alone have no feature which inhibits upward motion.
This problem also exists in the U.S. Pat. No. 5,779,391, issued to Knight. Viewing FIG. 1 and FIG. 16A, in combination, a block is shown having protrusions extending from the block side surfaces which slidably engage channels formed in adjacent blocks. Without cabling extending through the revetment mat, the blocks would also be susceptible to vertical lifting forces.
Cable or rope may be disposed through the blocks of a revetment mat in order to prevent upward lift, for instance as shown in the above mentioned references. However, often the cable may fray and break due to corrosion, rot, marine organisms and the like. Once the revetment mat is positioned in a waterway it is very difficult to replace the cable or rope. Moreover, it is difficult to remove the revetment mat from the waterway since the cables generally support the mattress during lifting.
In view of the deficiencies in known revetment blocks, it is apparent that a revetment block is needed for use with a revetment mat having a design which inhibits uplift of the revetment block and does not rely on a cable to inhibit hydraulic lift of the revetment block and necessarily the revetment mat.